Möbius sequence in a girl and arthrogryposis in her half-brother: distinct phenotypes caused by prenatal injuries

M?bius sequence is a congenital facial and abducens nerve palsy, frequently associated to abnormalities of extremities. Arthrogryposis multiplex congenital is defined as a congenital fixation of multiple joints seldom of neurogenic origin. Both sequences must have a genetic origin, but usually are sporadic cases related to environmental factors such as drugs exposition and maternal trauma. A 5-year-old girl and a 1-year-old boy were born with M?bius sequence and arthrogryposis multiplex congenital, respectively. During pregnancies, the mother had vaginal bleeding at 7 weeks and used crack (free-based cocaine) in the first trimester, respectively. The girl also has equinovarus talipes and autistic behavior. The boy has arthrogryposis with flexion contractures of the feet and knees. A vascular disruption, due to hemorrhage and cocaine exposure, causing a transient ischemic insult to embryos in a critical period of development may be responsible for distinct phenotypes in these cases.     

The role of immune checkpoint receptors in the malignant phenotype of cutaneous T cell lymphoma

Immune checkpoint receptors (ICR) modulate the immune response and are critical hubs for immunotherapy. However, data on their role in T lymphoid malignancies, such as cutaneous T cell lymphoma (CTCL), is sparse. We aimed to explore the role of ICR in the malignant features of transformed T lymphocytes and evaluate the effect of ICR-targeting monoclonal antibodies, often used as immunotherapy for solid tumors. We used the CTCL cell line HH and the Sézary cell line Hut78 to examine ICR expression and the effects of ICR inhibition on cell viability and proliferation. Despite their shared T cell progeny, the different CTCL cell lines exhibit markedly different ICR expression profiles. Programmed cell death-ligand 1 (PD-L1) was expressed by both cell lines, while programmed death-1 (PD-1) was expressed only by the HH cell line. Common to all malignant T cells was an autonomous hyper-proliferative state that did not require T cell receptor stimulation. A monoclonal antibody blocking PD-1 had a small but statistically significant augmenting effect on T cell proliferation. Of note, when the cells were exposed to ionizing radiation, healthy lymphocytes and those derived from the HH cell line were salvaged by anti-PD-L1. We show a regulatory role of ICR, mainly PD-1 and its ligand PD-L1, on cutaneous T cell malignancy.

     

Thiol Peroxidase Is an Important Component of Streptococcus pneumoniae in Oxygenated Environments

Streptococcus pneumoniae is an aerotolerant Gram-positive bacterium that causes an array of diseases, including pneumonia, otitis media, and meningitis. During aerobic growth, S. pneumoniae produces high levels of H₂O₂. Since S. pneumoniae lacks catalase, the question of how it controls H₂O₂ levels is of critical importance. The psa locus encodes an ABC Mn²⁺-permease complex (psaBCA) and a putative thiol peroxidase, tpxD. This study shows that tpxD encodes a functional thiol peroxidase involved in the adjustment of H₂O₂ homeostasis in the cell. Kinetic experiments showed that recombinant TpxD removed H₂O₂ efficiently. However, in vivo experiments revealed that TpxD detoxifies only a fraction of the H₂O₂ generated by the pneumococcus. Mass spectrometry analysis demonstrated that TpxD Cys⁵⁸ undergoes selective oxidation in vivo, under conditions where H₂O₂ is formed, confirming the thiol peroxidase activity. Levels of TpxD expression and synthesis in vitro were significantly increased in cells grown under aerobic versus anaerobic conditions. The challenge with D39 and TIGR4 with H₂O₂ resulted in tpxD upregulation, while psaBCA expression was oppositely affected. However, the challenge of ΔtpxD mutants with H₂O₂ did not affect psaBCA, implying that TpxD is involved in the regulation of the psa operon, in addition to its scavenging activity. Virulence studies demonstrated a notable difference in the survival time of mice infected intranasally with D39 compared to that of mice infected intranasally with D39ΔtpxD. However, when bacteria were administered directly into the blood, this difference disappeared. The findings of this study suggest that TpxD constitutes a component of the organism''s fundamental strategy to fine-tune cellular processes in response to H₂O₂.     

The trisomy 4p syndrome: Case report and review

We report a further case of trisomy 4p: a 5-year-old mentally retarded boy with characteristic facial features, eye abnormalities, flexion contractures, several bone anomalies, and hyperactivity. In a review of 27 cases (11♂, 16♀, 22 families) the cytogenetic and clinical data were tabulated and analyzed. Diagnosis is established by karyotype: there is always partial or apparently “total” trisomy of the short arm of chromosome 4. In 19 families a parent carried either a balanced translocation (16 times) or a pericentric inversion (3 times); 3 patients had de novo duplication of 4p. In several cases, additional deletions or trisomies were present. From the analysis of all cases, but particularly of the “pure” trisomies, the phenotypic spectrum of this condition was observed and found to be a specific multiple congenital anomaly/mental retardation (MCA/MR) syndrome. Its main features are a characteristic facial appearance, postnatal growth retardation, severe psychomotor retardation with or without seizures, microcephaly, and various major and minor anomalies.